<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>计算三角形面积</title>
    <script>
        var bottom = prompt("请输入三角形的底");
        var height = prompt("请输入三角形的高");
        alert(parseInt(bottom)*parseInt(height)*(1/2)); 
    </script>
</head>
<body>
    
</body>
</html>